The reliability, responsiveness and clinical utility of the Proximat: a new tool for measuring hip range of movement in children with cerebral palsy

Abstract

Background and purpose: Monitoring range of movement is a key aspect of managing hip problems in children with cerebral palsy. The aim of this study was to assess the clinical utility, reliability and responsiveness of a new measurement tool, the Proximat, for hip range of movement.

Method: Passive hip abduction, adduction, medial and lateral rotation were measured by using the Proximat on 26 children with cerebral palsy attending three special schools: 16 of whom are boys, mean age = 7 years and 6 months (standard deviation = 4.2 years), range 2-15 years. Testing was undertaken by two physiotherapists to assess interrater reliability and repeated the following day to assess test-retest reliability. Total, random and systematic errors were calculated for interrater and test-retest.

Results: The Proximat was quick and easy to use and acceptable to the children. High reliability was found for all movements (intraclass correlation coefficient = 0.83-0.93) with reasonable responsiveness; total error was 2.5-12 degrees. Most of the error was random with little evidence of systematic bias.

Conclusions: The Proximat is a reliable, responsive and acceptable method of measuring passive hip movements in children with cerebral palsy in day-to-day clinical practice. A change of 8-12 degrees is needed to overcome measurement error and to indicate that a 'true' change in range of movement has occurred.